The present invention relates generally to a force producing apparatus and, more particularly, to an air-to-air pressure intensifier for providing relatively large forces to machines such as clamps, grippers, presses and punches.
Many systems utilize the basic principle of inserting a rod into an enclosed oil-filled chamber to produce a relatively high force over a short working stroke. These devices utilize air pressure and/or springs to force the liquid into a working chamber before the pressure is intensified by insertion of the rod. Air at a relatively low pressure provides the force to insert the rod into the liquid chamber to intensify force output from the device.
While air-to-oil intensifiers have provided desirable functions in the workplace, simplified devices may be desirable. For example, many air-to-oil intensifiers exhibit oil leaks and require an oil level indicator to alert an operator when oil must be added. Air sometimes becomes trapped within the liquid chambers causing a reduced force output. An operator is required to bleed the air from the chamber. Furthermore, these devices typically require high pressure seals and hydraulic fluid that have a predetermined service life which is recommended for replacement after a certain number of cycles.
Some air-to-oil intensifiers utilize an external oil tank that must be mounted in a vertical orientation. Mounting this type of unit on a robot may pose a challenge due to the robot changing positions during operation. Additional hoses and piping must be incorporated to mount such an oil reservoir.
Other devices known as air toggle presses are also used to produce high forces. These devices typically have a limited working stroke and weight. Furthermore, toggle presses typically only produce high forces near the bottom of the ram stroke.
Accordingly, it may be beneficial to provide an air-to-air pressure intensifier operable to produce relatively high forces over a short working stroke without the need for a liquid filled chamber. It may also be beneficial to provide a device eliminating the need for an external oil reservoir.
An intensifier constructed in accordance with the present invention is operable to supply force and includes a housing defining a cavity. A ram is slidably positioned within the cavity and partially extends from the housing. The intensifier also includes a force transfer rod and a plurality of power pistons. The ram is moveable between retracted and extended positions along a longitudinal axis. The force transfer rod is selectively moveable between a retracted position where the force transfer rod is not axially aligned with the ram and an advanced position where the force transfer rod is axially aligned with the ram. The plurality of power pistons are axially aligned with each other and the ram. The power pistons are selectively operable to provide an output force to the ram when the force transfer rod is in the advanced position.